Every now and then I come across someone on the subway who defies easy categorization. I remember, for instance, a man who boarded the 3 train in Brooklyn a few years ago wearing military fatigues and a bandolier packed with little glass bottles of liquids. “Who is man enough to buy my fragrances?” he shouted. (When one rider replied that he wasn’t sure, the man responded, “Are you man enough to kill a hooker in Moscow with a crowbar?”) More recently, there was a man on the uptown 6 wearing a pair of oversized New Year’s glasses—the ones where the 0’s serve as eyeholes—who played atonal jazz on his saxophone and asked for no monetary compensation in return. I could keep going, but no doubt anyone who has lived in a city for any length of time has their own mental list of these self-styled subterranean eccentrics, grouped together not so much by any particular characteristic other than the fact that they seem only to exist underground.